The red-crowned crane (Grus japonensis), also called the Japanese crane (traditional Chinese: 丹頂鶴; simplified Chinese: 丹顶鹤; pinyin: Dāndǐng Hè; Japanese: 丹頂鶴 or タンチョウヅル; rōmaji: tanchōzuru; Korean: 두루미; romaja: Durumi; the Chinese character '丹' means 'red', '頂/顶' means 'crown' and '鶴/鹤' means 'crane') or Manchurian Crane, is a large East Asiancrane and among the rarest cranes in the world. In some parts of its range, it is known as a symbol of luck, longevity and fidelity.

Adult red-crowned cranes are named for a patch of red bare skin on the crown, which becomes brighter in the mating season. Overall, they are snow white in color with black on the wing secondaries, which can appear almost like a black tail when the birds are standing, but the real tail feathers are actually white. Males are black on the cheeks, throat and neck, while females are pearly gray in these spots. The bill is olive green to greenish horn, the legs are slaty to grayish black, and the iris is dark brown.[2]

This species is among the largest cranes, typically measuring about 150 to 158 cm (4 ft 11 in to 5 ft 2 in) tall and 101.2–150 cm (3 ft 4 in–4 ft 11 in) in length (from bill to tail tip). Across the large wingspan, the red-crowned crane measures 220–250 cm (7 ft 3 in–8 ft 2 in).[3][4][5][6] Typical body weight can range from 4.8 to 10.5 kg (11 to 23 lb), with males being slightly larger and heavier than females and weight ranging higher just prior to migration.[7][8][9] On average, it is the heaviest crane species, although both the sarus and wattled crane can grow taller and exceed this species in linear measurements.[8][10][11] On average, adult males from Hokkaido weighed around 8.2 kg (18 lb) while adult females there averaged around 7.3 kg (16 lb) while a Russian study found males averaged 10 kg (22 lb) and females averaged 8.6 kg (19 lb) and in some cases females could outweigh their mates despite the males slightly larger average body mass. Another study found the average weight of the species to be 8.9 kg (20 lb).[8][12][13] The maximum known weight of the red-crowned crane is 15 kg (33 lb).[14][15] Among standard measurements, the wing chord measures 50.2–74 cm (19.8–29.1 in), the exposed culmen measures 13.5–17.7 cm (5.3–7.0 in), tail length is 21.5–30 cm (8.5–11.8 in) and the tarsus measures 23.7–31.9 cm (9.3–12.6 in).[12]

In the spring and summer, the migratory populations of the red-crowned crane breed in Siberia (eastern Russia), northeastern China and occasionally in northeastern Mongolia[1] (i.e., Mongol Daguur Strictly Protected Area). The breeding range centers in Lake Khanka, on the border of China and Russia. Normally the crane lays 2 eggs, with only one surviving. Later, in the fall, they migrate in flocks to Korea and east-central China to spend the winter.[1]Vagrants have also been recorded in Taiwan.[1] In addition to the migratory populations, a resident population is found in eastern Hokkaidō in Japan.[1] This species nests in wetlands and rivers. In the wintering range, their habitat is comprised mainly by paddy fields, grassy tidal flats, and mudflats. In the flats, the birds feed on aquatic invertebrates and, in cold, snowy conditions, the birds switch to mainly living on rice gleanings from the paddy fields.

Red-crowned cranes have a highly omnivorous diet, though the dietary preferences have not been fully studied. They eat rice, parsley, water plants, carrots, reed buds, acorns, buckwheat and a variety of water plants. The animal matter in their diet consists of fish, including carp and goldfish, amphibians, especially salamanders, snails, crabs, dragonflies, small reptiles and other birds, especially waterfowl. They seem to prefer animal food matter throughout the year, although rice is now essential to survival for wintering birds in Japan and grass seeds are an important food source. While all cranes are ominivorous, per Johnsgard, the two most common crane species today (the sandhill and common cranes) are amongst the most herbivorous species while the two rarest species (the red-crowned and whooping cranes) are perhaps the most carnivorous species. When feeding on plants, red-crowned cranes exhibit a preference for plants with high content of crude protein and low content of crude fiber.[16]

They typically forage by keeping the head close to the ground, jabbing the bill into mud when something edible is encountered. When capturing fish or other slippery prey, they may quickly jab in a similar fashion to a heron. Although animal prey can be swallowed whole, usually red-crowned cranes more often tears up prey by grasping with its bill and shaking it vigorously, eating pieces as they fall apart. Most foraging occurs in wet grasslands, cultivated fields, in shallow rivers or on lakeshores.

The population of red-crowned cranes in Japan is essentially non-migratory, with the race in Hokkaido moving only 150 km (93 mi) to its wintering grounds. Only the mainland population experiences a long-distance migration. They leave their wintering grounds in spring by February and are established on territories by April. In fall, they leave their breeding territories in October and November, with the migration fully over by mid-December.

Flock sizes are affected by the small numbers of the red-crowned crane and, given their largely carnivorous diet; some feeding dispersal is needed in natural conditions. Wintering cranes have been observed foraging, variously, in family groups, pairs and singly, although all roosting is in larger groups (up to 80 individuals) with unrelated cranes. By the early spring, pairs begin to spend more time together, with non-breeding birds and juveniles dispersing separately. Even while not nesting, red-crowned cranes tend to be aggressive towards conspecifics and maintain a minimum distance of 2 to 3 m (6.6 to 9.8 ft) to keep out of pecking range of other cranes while roosting nocturnally during winter. In circumstances where a crane violates these boundaries, they may be violently attacked.[17]

It is believed that breeding maturity is reached at three or four years of age. All mating and egg-laying is largely restricted to April and early May. A red-crowned crane pair will duet in various situations, helping to establish formation and maintenance of the pair bond, as well as territorial advertisement and agonistic signaling. The pair move rhythmically until they are standing close, throw their heads back and let out a fluting call in unison, often triggering other pairs to start duetting as well. As it is occurs year around, the social implications of dancing are complex in meaning. However, dancing behavior is generally thought to show excitement in the species.[13][18]

Pairs are territorial during the breeding season.[19] Nesting territories range from 1 to 7 km (0.62 to 4.35 mi) and are often the same year after year. Most nesting territories are characterized by flat terrain, access to wetland habitat and tall grasses. Nest sites are selected by females but built by both sexes and are frequently in a small clearing made by the cranes, either on wet ground or shallow water over waters no more than 20 to 50 cm (7.9 to 19.7 in) deep. Sometimes, nests are built on the frozen surface of water as frigid temperatures may persist well into nesting season.[20] Nest building takes approximately a week.[17] A majority of nests contain two eggs, though 1 to 3 have been recorded. Both sexes incubate the eggs for at least 30 days. They also both feed the young when they hatch. Staying in the nest for the first few weeks, the young start to follow their parents as they forage in marshes by around 3 months of age. New hatchlings weigh about 150 g (5.3 oz) and are covered in yellow natal down for two weeks.[13][21] By early fall, about 95 days after hatching, the young are fledged and are assured fliers by migration time. Although they can fly well, crane young remain together with their parents for around 9 months.[6] Young cranes maintain a more high pitched voiced that may serve to distinguish them from outwardly similar mature birds, this stage lasting until the leave parental care.[13][22] The average adult lifespan is around 30 to 40 years, with some specimens living to 70 years of age in captivity. It is one of the longest living species of bird.[6][23]

With their height averaging 1.5 meters (5 ft), their large size deters most predators.[24] As a result, red-crowned cranes often react indifferently to the presence of other birds such as small raptors; with harriers, falcons, owls and small buzzards being allowed to hunt small prey near a crane nest without any of these parties harassing each other. On the other hand, birds more likely to be egg or nest predators, such as corvids, some buzzards, and various eagles, are treated aggressively and will be threatened until they leave the crane's territory. Mammalian carnivores, including gray wolves, red foxes, badgers, raccoon dogs, Eurasian lynxes and domestic dogs are attacked immediately, with the parent cranes attempting to jab them in the flanks until the predator leaves the vicinity, sometimes killing smaller enemies such as foxes.[25] Occasionally, losses at the nest occur to some of the above predators. Introduced American mink on Hokkaido are one of the most successful predators of eggs and nestlings.[26] Also, immature and unwary adult cranes may be killed by the largest raptors, such as sea eagles, or mammalian carnivores, though this is rare, especially with adults. White-naped cranes often nest near red-crowned cranes but competition between these species for food in a common nesting area is lessened due to the greater portion of vegetation in the white-naped's diet.[27] In cases where interactions turn aggressive between white-naped and red-crowned cranes, red-crowned cranes are dominant, as expected due to their considerably larger size.[28]

The estimated total population of the species is only 2,750 in the wild, including about 1,000 birds in the resident Japanese population.[1] Of the migratory populations, about 1,000 winter in China (mainly at the Yellow River delta and Yancheng Coastal Wetlands), and the remaining winter in Korea.[1] It is endangered and received this status on June 2, 1970.

The National Aviary in Pittsburgh, Pennsylvania ran a program where U.S. zoos donated eggs which were flown to Russia and raised in the Khinganski Nature Reserve and released into the wild. This program sent 150 eggs between 1995-2005. The program has been put on hold in order to concentrate on different crane conservation programs in Russia, such as education and fire suppression (red-crowned crane ssp.). Several hundred red-crowned cranes are kept in zoos around the world.[29] Assuredly, the international efforts of Russia, China, Japan and Korea are needed to keep the species from extinction. The most pressing threat is habitat destruction, with a general lack of remaining pristine wetland habitats for the species to nest in. In Japan, there is little proper nesting habitat and the local breeding population is close to the saturation point.[2][17]

In China, the red-crowned crane is often featured in myths and legends. In Taoism, the red-crowned crane is a symbol of longevity and immortality. In art and literature, immortals are often depicted riding on cranes. A mortal who attains immortality is similarly carried off by a crane. Reflecting this association, red-crowned cranes are called xian he (traditional Chinese: 仙鶴; simplified Chinese: 仙鹤; pinyin: xiānhè; literally: "fairy crane" or "crane of the immortals"). The red-crowned crane is also a symbol of nobility. Depictions of the crane have been found in Shang Dynasty tombs and Zhou Dynasty ceremonial bronzeware. A common theme in later Chinese art is the reclusive scholar who cultivates bamboo and keeps cranes. Some literati even reared cranes and trained them to dance to guqin music.

Because of its importance in Chinese culture, the red-crowned crane was selected by the National Forestry Bureau of the People's Republic of China as a candidate for the title of national animal of China. This decision was deferred due to the red-crowned crane's Latin name translation as "Japanese crane".[30]

In Japan, this crane is known as the tanchōzuru and is said to live for 1,000 years. A pair of red-crowned cranes were used in the design for the Series D 1000 yen note (reverse side). In the Ainu language, the red-crowned crane is known as sarurun kamuy or marsh kamuy. At Tsurui they are one of the 100 Soundscapes of Japan. Cranes are said to grant favours in return for acts of sacrifice, as in Tsuru no Ongaeshi ("crane's return of a favor").

Given its reputation, Jerry Huff, an American branding expert, recommended it as the international logo of Japan Airlines, after seeing a representation of it in a gallery of samurai crests. Huff wrote “I had faith that it was the perfect symbol for Japan Air Lines. I found that the Crane myth was all positive—it mates for life (loyalty), and flies high for miles without tiring (strength.)”[31]

In Korea, the red-crowned crane is called 'Durumi' and it is considered a symbol of longevity, purity and peace. Korean seonbis regarded the bird as an icon of their constancy. The red-crowned crane is depicted on the in Korean 500 won coin and is the symbol of Incheon.

^Ma, Y-C. 1981. The annual cycle of red-crowned crane. In: Lewis JC, Masatomi H. (Eds.). 1981. Crane research around the world: Proceedings of the International Crane Symposium at Sapporo Japan in 1980 and papers from the World Working Group on Cranes, International Council for Bird Preservation. Baraboo, WI: International Crane Foundation.

^Vinter, S.V. 1981. Nesting of the red-crowned crane in the Central Amur Region. In: Lewis JC, Masatomi H. 1981. Crane research around the world: Proceedings of the International Crane Symposium at Sapporo Japan in 1980 and papers from the World Working Group on Cranes, International Council for Bird Preservation. Baraboo, WI: International Crane Foundation.

Three White Cranes, Two Flyways, One World An educational website that links schools along the eastern whooping crane flyway in the United States with schools along the eastern flyways of the Siberian and red-crowned cranes in Russia and China.